1. Field of the Invention
The present invention relates to media devices and, more particularly, to equalizer effects for media being presented on media devices.
2. Description of the Related Art
Media players, such as digital media players, are specialized portable computing devices that store and present (e.g., play, display) digital media (e.g., music, videos, or images). Often media players are small hand-held devices with limited media storage capacity and limited media management capability. As a result, media players typically associate with a host computer. The host computer can utilize an application resident on the host computer to perform media management for the host computer and the media player, such management including transfer of the media items and their attributes between the host computer and the media player. One such application is iTunes™, produced by and available from Apple Inc. of Cupertino, Calif. An example of a popular media player is an iPod™ which is also produced by and available from Apple Inc.
iTunes can display a graphic equalizer for a user of the host computer. With iTunes, users can specify a set of equalizer settings by selecting one of a list of equalizer presets. Equalizer presets are equalizer settings for various frequency bands that are predetermined and available for selection by users. In addition, users can manually change the settings of a graphic equalizer to achieve a desired (e.g., custom) frequency response for particular media items. To a limited extent, equalizer settings for media items can be transferred from iTunes to the media player. Media players typically have limited computational resources and a small form factor. Consequently, there are difficulties with implementing a graphic equalizer on a media player. One prior solution involves manual conversion of predetermined equalizer settings for the equalizer presets to a simplified filter structure. Such a manual conversion can reduce computational requirements needed to implement the equalizer adjustments on the media player. Unfortunately, however, this prior solution based on manual conversion is time consuming and only effective when the equalizer settings are known and remain fixed. Since the equalizer settings must be fixed, the prior solution also does not support user manipulation of equalizer settings. Other prior solutions involve complex optimization algorithms and/or curve fitting of finite impulse response (FIR) filters. However, these approaches are computationally intensive and not guaranteed to find acceptable solutions, and the resulting filter is usually two or more orders of magnitude more computationally expensive than the original graphic equalizer.
Thus, there is a need for improved approaches to flexibly implement graphic equalizers on media players with limited computational resources.